Antimicrobial resistance against colistin has emerged worldwide threatening the efficacy of one of the last-resort antimicrobials used for the treatment of Enterobacteriaceae. To investigate the presence of the recently identified colistin resistance genes (mcr-4, mcr-5) in China, we established PCRs to detect mcr-4 and mcr-5 on 213 anal and 1,339 nasal swabs from apparently healthy pigs (n = 1,454) in nine provinces, and 1,696 cloacal and 1,647 oropharyngeal samples from poultry (n = 1,836) at live-bird markets in 24 provinces of China. The prevalence of the mcr-4 in swine swabs (41.4%; 642/1,552) was significantly higher than in swabs from poultry (11.5%; 384/3,343). The mcr-4 gene was found in geese (49.5%, 54/109), chickens (17.2%, 257/1,498), pigeons (17.2%, 17/99) and ducks (15.4%, 20/130). In a similar trend, the prevalence of the mcr-5 in swine swabs (33.1%; 514/1552) was significantly higher than in swabs from poultry (5.6%; 187/3,343). The mcr-5 was identified in geese (17.4%, 19/109), chickens (9.9%, 148/1,498), ducks (7.7%, 10/130) and pigeons (3%, 3/99). The mcr-4 prevalence in the nasal swabs from pigs (59.2%, 58/98) was significantly higher than that in anal swabs (29.6%, 29/98) (P<0.001). Similarly, the mcr-5 prevalence in the nasal swabs from pigs (61.2%, 60/98) was significantly higher than in anal swabs (44.9%, 44/98) (P = 0.02), and significantly higher in oropharyngeal swabs (7.2%, 109/1,507) than in the cloacal swabs (3.7%, 56/1,507) (P<0.001). This study further confirms the presence of the mcr-4 and mcr-5 in animals and indicates these genes are prevalent and widespread in food producing animals (pig and poultry) in China. Future studies are needed to characterize the bacteria carrying the mcr-4 and mcr-5 and their locations on plasmids and/or the bacterial chromosomes, and determine co-resistances in the mcr-4 and mcr-5 positive strains.

@article{8560346,
abstract = {Antimicrobial resistance against colistin has emerged worldwide threatening the efficacy of one of the last-resort antimicrobials used for the treatment of Enterobacteriaceae. To investigate the presence of the recently identified colistin resistance genes (mcr-4, mcr-5) in China, we established PCRs to detect mcr-4 and mcr-5 on 213 anal and 1,339 nasal swabs from apparently healthy pigs (n = 1,454) in nine provinces, and 1,696 cloacal and 1,647 oropharyngeal samples from poultry (n = 1,836) at live-bird markets in 24 provinces of China. The prevalence of the mcr-4 in swine swabs (41.4\%; 642/1,552) was significantly higher than in swabs from poultry (11.5\%; 384/3,343). The mcr-4 gene was found in geese (49.5\%, 54/109), chickens (17.2\%, 257/1,498), pigeons (17.2\%, 17/99) and ducks (15.4\%, 20/130). In a similar trend, the prevalence of the mcr-5 in swine swabs (33.1\%; 514/1552) was significantly higher than in swabs from poultry (5.6\%; 187/3,343). The mcr-5 was identified in geese (17.4\%, 19/109), chickens (9.9\%, 148/1,498), ducks (7.7\%, 10/130) and pigeons (3\%, 3/99). The mcr-4 prevalence in the nasal swabs from pigs (59.2\%, 58/98) was significantly higher than that in anal swabs (29.6\%, 29/98) (P{\textlangle}0.001). Similarly, the mcr-5 prevalence in the nasal swabs from pigs (61.2\%, 60/98) was significantly higher than in anal swabs (44.9\%, 44/98) (P = 0.02), and significantly higher in oropharyngeal swabs (7.2\%, 109/1,507) than in the cloacal swabs (3.7\%, 56/1,507) (P{\textlangle}0.001). This study further confirms the presence of the mcr-4 and mcr-5 in animals and indicates these genes are prevalent and widespread in food producing animals (pig and poultry) in China. Future studies are needed to characterize the bacteria carrying the mcr-4 and mcr-5 and their locations on plasmids and/or the bacterial chromosomes, and determine co-resistances in the mcr-4 and mcr-5 positive strains.},
articleno = {e0193957},
author = {Chen, Li and Zhang, Jilei and Wang, Jiawei and Butaye, Patrick and Kelly, Patrick and Li, Min and Yang, Feng and Gong, Jiansen and Yassin, Afrah Kamal and Guo, Weina and Li, Jing and Song, Chunlian and Wang, Chengming},
issn = {1932-6203},
journal = {PLOS ONE},
keyword = {KLEBSIELLA-PNEUMONIAE,CLINICAL ISOLATE,ENTEROBACTERIACEAE,EPIDEMIOLOGY,PREVALENCE,PLASMID},
language = {eng},
number = {3},
pages = {10},
title = {Newly identified colistin resistance genes, mcr-4 and mcr-5, from upper and lower alimentary tract of pigs and poultry in China},
url = {http://dx.doi.org/10.1371/journal.pone.0193957},
volume = {13},
year = {2018},
}